As a coupler used to couple an attaching target to an attached target, for example, in the field of cameras, there is one used for a sling as disclosed in Patent Literature 1 below. The sling in Patent Literature 1 is one for making it possible for a user of a camera to carry the camera with both hands free, and includes an annular-shaped shoulder strap and a coupler attached to the shoulder strap. The coupler is a single member that is not a separable structure, and used to couple the shoulder strap obliquely slung over the body of the user and the camera together. The coupler includes a male screw part, and by screwing the mail screw part into a female screw part of the camera, the camera is fixed to the coupler.